Feed mechanism for railway sewing machines



May 18, 1943 c. E. SMITH ETIAL 2,319,370

FEED MECHANISM FOR RAILWAY SEWING MACHINES Filed Nov. 13, 1940 mgA Patented May 18, 1943 FEED MECHANISM FOR RAILWAY SEWING V 1 K l MACHINES i ClifiordEd'gar. Smith and Frank D. Lockman,

Lockhart, S. 0., assignors to Curtis & Marble Machine Company, Worcester, Mass, at corporation of Massachusetts Appli'cation November 13, 1940, Serial No. 365,538

r 1 Claim. (Cl. 1 122) -This invention relates to the sewing together of lengths of cloth preparatory to certain textile finishing operations. It is customary to stitch the warp ends of consecutive pieces of cloth together by power sewing machines, which make different kinds of seams including the so-called Merrow or butted seam. Ends of cloth which are Merrow-stitched are united by long loops extending warpwise or transversely of the cloth .edges, and the abutted cloth ends are aligned in a single plane after a Merrow seam is opened out. 1

Such a seam is obviously of a rather loose and open construction and it is sometimes desirable to strengthen or reenforce the-seam by placing the stitches closer together at the clothselvages.

Such a reenforced Merrowor butted seam is shown in the prior patent to Talmadge, No. 1,992,690, issued February 26, 1 935. The stitching may be done by feeding the cloth past a stationary sewing machine, or by moving the sewing machine hea'cl along weft-wise of the cloth. The latter arrangement is commonly termed a railway sewing machine.

Our present invention relatesto means for feeding a railway sewing machine at such relative speeds as will produce a Merrow or butted seam with the selvage edge portions reenforced by closer stitching.

A further object of our invention is to provide feeding mechanism for such purposes which will automatically change the rate of feed as different portions of the seam are to be stitched.

Our invention further relates to arrangements and combinations of parts which will be hereinafter described and more particularly pointed out in the appended claim.

A preferred form of the invention is shown in the drawing, in which Fig. 1 is a partial plan view, partly in section, of a railway sewing machine embodying our improvements;

Fig. 2 is a sectional side elevation, taken along the line 22 in Fig. 1;

Fig. 3 is a sectional plan view, taken along the line 3-3 in Fig. 2; and

Fig. 4 is a plan view of portions of cloth stitched together with a Merrow seam and reenforced selvages.

Referring to the drawing, we have shown a portion of the usual cross rail ID for a railway sewing machine, which rail extends from side to side of the machine and forms a fixed support for the railway stand I2.

are to be stitched together.

have coacting dove-tailed guideways l4 and IS. A gib I6 is provided for accurate sliding adjustment. v

A Merrow sewing machine or head is mounted on the stand I 2 and has a cloth support 2| adapted to pass under and support the superposed edges of the pieces ofcloth which The details of the sewing machine head are not shown but are of the usual commercial construction. r i

A driving shaft 24 is rotatably mounted in bearings on the stand 12 and this. shaft may be rotated by a belt 25 passing over a grooved pulley 26 on the shaft 24 and under offset idler pulleys 21 and 28. The belt 25 extends the entire length of the cross rail or support In and has driving engagement with the pulley 26 and with a driving pulley 29 for the sewing machine 20 in every position of the stand I2,as the stand and sewing machine are moved across the machine and weftwise of the cloth. The pulley 29 transmits power to the stitching mechanism in the sewing machine 20, which may be of a usual construction.

The shaft 24 is also provided with a worm so which meshes with a worm-wheel 3| loosely rotatable on an upright shaft 32. The shaft 32 is mounted in a bearing 33 (Fig. 2) fixed to the railway stand I2.

The shaft 32 and bearing 33 extend downward through the stand l2, and a gear and pinion 4| are fixed to the lower end of the shaft 32. A clutch collar is slidable but non-rotatable on the upper end of the shaft 32. The clutch collar 45 and worm-gear 3| have coacting conical friction surfaces which may be operatively engaged by tightening a hand wheel 41, mounted on the threaded upper end 48 of the shaft 32. One or more springs 49 may be provided to separate the friction surfaces whenthe hand 'wheel 4'! is released.

The gear 40 is positionedto mesh with a rack 50 fixed in position under the cross rail or support l0 during normal cloth feed, and the pinion 4| is positioned to mesh with similarly located short rack bars 52 and 52 for slow feed as the railway sewing machine stitches one or the other of the cloth selvage portions.

The operation to be performed is illustrated in Fig. 4, which shows two pieces of cloth C and C joined by Merrow stitches or loops L which are relatively spaced apart, as shown at S, in the middle portion and which are relatively close together, as shown at S and S in the selvage The cross rail or support In and the stand I2 6 portions.

.as they become alternately operative.

Assuming that the railway head has been placed at the right-hand side of the machine and beyond the selvage, the hand wheel 41 will then be tightened to connect the worm wheel 3| to the upright shaft 32, after which the belt 25 will be set in motion.

When the belt begins to move, the pulleys 26 and 29 will be actuated to start the feed and the stitching operation. The worm 30 will be rotated and will act through the worm-gear 3|, shaft 32, pinion 4| and rack bar 52 to feed the stand I2 and supported parts relatively slowly along the support I0, thus producing the closely placed stitches S shown in Fig. 4.

The rack bar 52 is of such length that the pinion 4| clears the rack bar 52 and the gear 40 engages the rack 50 when the desired number of closely spaced stitches S have been inserted.

As the shaft 32 always rotates at the same speed, the rate of travel of the stand |2 will obviously be increased proportionately to the difference in diameters of the gear 49 and the pinion 4|.

The stand I2 and the stitching mechanism will thus travel at increased speed and will insert more widely spaced stitches S until the opposite selvage is approached, when the gear 40 will clear the rack 50 and the pinion 4| will engage the second rack bar 52 The closely spaced stitches S will then be inserted in the second selvage.

' The feeding of the sewing machine across the entire width of the fabric is thus automatic, as is also the change in rate of feed and in stitch spacing, all of which are dependent on the different diameters of the pinion 4| and the gear 40 After the stitching has been completed, it is the usual practice to stop the belt 25, release the .hand wheel 41, and return the stand I2 and railway sewing machine to right-hand initial position manually.

It is obvious that the rack 50 and rack bars 52 and 52 may be of any desired length for different widths of cloth and for different widths of reinforcement, and it is also obvious that the gear 40 and pinion 4| may be difierently proportioned to increase or decrease the change in rela* tive stitch spacing.

Having thus described our invention and the advantages thereof, we do not wish to be limited to the details herein disclosed, otherwise than as set forth in the claim, but what we claim is:

In a railway sewing machine, a fixed support, a sewing machine and stand slidable on said support, power means to feed said stand along said support including a driven shaft mounted in fixed axial position on said stand and rotatable on an axis perpendicular to the path of travel of said stand, said shaft having a gear and an adjacent pinion fixed thereon and rotatable therewith in parallel planes, with said gear of substantially greater effective diameter than said pinion, a rack on said fixed support which extends longitudinally thereof in the plane of movement of said gear and which is engageable by said gear, and two spaced rack bars on said fixed support which extend longitudinally thereof in the plane of movement of said pinion and which are engageable by said pinion, said rack bars and said rack being so relatively positioned longitudinally on said support that they are automatically, alternately and successively engaged by said pinion, said gear and again by said pinion during continued travel of said sewing machine in a forward direction on said support, and said feeding means being thereby rendered effective to feed said sewing machine and stand at successive slow, fast, and slow rates along said support and without change in the rate of stitch formation.

CLIFFORD EDGAR SMITH. FRANK D. LOCKMAN. 

